Is deceit allowed in Islam to spread the religion?

[robvalue]

Lying implies intent. It can't simply be about saying things that aren't true, since that applies to just about everything they say.

If they are knowingly putting out falsehoods about their own religion, book or whatever, that's pretty sad in the first place. It's often entirely pointless too since it's never been easier to fact check things. You're not likely to fool anyone who doesn't already believe the same thing.